Analyte detection in physiological fluids, e.g., blood or blood derived products, is of ever increasing importance to today's society. Analyte detection assays find use in a variety of applications, including clinical laboratory testing, home testing, etc., where the results of such testing play a prominent role in diagnosis and management in a variety of disease conditions. Analytes of interest include glucose for diabetes management, cholesterol, and the like. In response to this growing importance of analyte detection, a variety of analyte detection protocols and devices for both clinical and home use have been developed.
One type of method that is employed for analyte detection is an electrochemical method. In such methods, an aqueous liquid sample is placed into a reaction zone in an electrochemical cell comprising two electrodes, i.e., a reference and working electrode, where the electrodes have an impedance which renders them suitable for amperometric measurement. The component to be analyzed is allowed to react directly with an electrode, or directly or indirectly with a redox reagent to form an oxidizable (or reducible) substance in an amount corresponding to the concentration of the component to be analyzed, i.e., analyte. The quantity of the oxidizable (or reducible) substance present is then estimated electrochemically and related to the amount of analyte present in the initial sample.
A problem faced by manufacturers and users of these types of electrochemical test strips is reagent degradation due to water exposure. For example, when the reagent composition of such strips is exposed to normal environmental humidity, the response of the test strip can change dramatically and therefore confound the results obtained with the strip.
As such, there is continued interest in the identification of new electrochemical strip configurations in which the reagent composition of the strip is protected from contact with environmental humidity. Of particular interest would be the development of a card from which a plurality of test strips could be singulated, where the reagent composition in each card is protected from water mediated degradation.
Relevant Literature
Patent documents of interest include: U.S. Pat. Nos. 5,708,247; 5,942,102; 5,951,836; 5,972,199; 5,989,917; 5,997,817; 6,151,110; 6,125,292; WO 97/18465; WO 97/27483 and EP 871 033.